Dad and his friend were out shooting prairie dogs sometime in the mid-80's. Friend needs a "facility" and there's an outhouse nearby. He gets in, appropriately dis-robed and perched upon the "throne", and the rattling starts. The snake is visible in the corner, not under him in the deposit zone, and much too far away for any manner of effective strike. IIRC there was a rimfire pistol handed to the outhouse occupant who then dispatched the snake accordingly.
Not nearly as harrowing a tale as inadvertently pooping on a bear.